Concrete in the 22nd Century
Ken DayInnovative Concrete Technologist
Hon. Member, and founding committee member, of CIA
Is it Useful to Attempt Prediction?
An accurate prediction of the situation 100yrs from now may
seem unlikely
But some of my concepts from the early 1950s are only now beginning to spread widely
Can We Influence the Future?
Can we afford such delay?
Why does it happen?
Some things introduced 100 years from now may already be available,
but struggling for acceptance
The Climate of Change
There are huge changes due to admixtures, resource shortages, pollution considerations, and the
computer revolution
Concrete can be made without cement and reinforced without steel
It can be a self-compacting fluid
What will concrete be like?
Reactive Powder “concrete” essentially mortar, often with fibres,
with strength of several hundred MPa has been produced
Concrete of over 150MPa is now being used in precast bridges in USA
(and we thought their technology lags!)
What will concrete be like?
There is a rapidly increasing trend to Self- Compacting Concrete (SCC)
This matches the reduced availability of skilled site personnel and the reduced
tolerance for visual defects and for excessive noise and industrial injuries
Can We Cope with this?
These new concretes rely heavily on chemical admixtures, pozzolans and other finely divided materials
Concrete has become a high tech material and is becoming more so
What is the significance of this?
Is Concrete Important?
The production of concrete is used by some economists as a measure of a
country’s economic strength
– even it’s degree of civilization
Population is increasing worldwide but in some countries there is already a tax on
carbon dioxide generation
How Much Concrete Can We Afford?
Concrete is not just another material it is surpassed only by water as the most used material on earth
So it has an enormous impact on the environment, on capital expenditure, on resource consumption, and on pollution
How Durable should Concrete be?
Do we want our concrete to last 2000 years or 20 years?
The most expensive, most resource-consuming concrete is
that which has to be replaced
What Resources will be available?
Is there a limit to the resources available for the production of
concrete?
– and will it all be Portland Cement concrete?
Is Concrete Eco-Friendly?
Portland Cement production is already second only to the automobile as the major
generator of carbon dioxide -greenhouse gas!
What will the answer be?
Available Resources
We cannot continue to throw away mountains of fly ash and
slag
But will there always be such mountains?
How Will We Use Them?
If so, will we use them alkali-activated in geopolymer concrete, with no Portland Cement at all?
Or will we use High Strength, High Durability concrete to make thinner,
lighter structural members?
An Interesting Long-Shot
Has basalt fibre reinforcement a future?
(similar to glass fibre but much higher melting point)
Significance for Education in Concrete Technology
Need for flexibility – cannot teach ability to invent but must not stand
in way
New developments as likely to come from chemists, geologists, IT analysts etc, as from concrete technologists
Significance for Education in Concrete Technology
Practitioners as well as students must learn how to keep up to date
Continued Professional Development certainly required
A qualification in structural design is an inadequate basis for
specification and control
Significance for Education in Concrete Technology
ill-informed specifiers have held back progress for decades,
especially in USA
There will be a legal requirement for an appropriate qualification
before being allowed to specify or control concrete
Significance for Education in Concrete Technology
Unfortunately neither CIA nor ACI ordinary
membership provides this
Significance for Education in Concrete Technology
Will there be an appropriate grade in future?
A qualification such as that provided by the UK Institute of
Concrete Technology is required
How will Concrete be Produced and Controlled?
Still likely to be centrally mixed and delivered by truck
High-tech heavily computerised plants providing the ultimate in QC
How will Concrete be Produced and Controlled?
There will be well-proven, tightly controlled mixes with last minute
adjustment for all available factors (slump, temperature and QC data on materials and concrete) (JIT!)
How will Concrete be Produced and Controlled?
Trucks will have built-in devices to provide fine-tuned
workability control
(already available but rarely installed)
How will Concrete be Purchased?
Via Internet (except large projects)
Purchaser will nominate brief requirements
Computer will offer nearest standard mix and state properties
and price
How will Concrete be Purchased?
If stated properties not acceptable, purchaser will tighten specification and Computer will offer revised mix (and revised
price!)
Regular and large customers will have code number to give agreed discount
Conclusions
Look for factors affecting actual durability,
impermeability, dimensional stability, strength,
environmental friendliness etc
Conclusions
Rather than preconceived (and probably outdated)
ideas of maximum or minimum contents of
particular materials and of grading requirements.
Conclusions
Critical knowledge is of:
•what is involved in the realistic evaluation of mix proposals
Conclusions
Critical knowledge is of:
•how to detect change in the quality of a continued supply of material and problems in the operation of a production facility
Conclusions
WE MUST AVOID ERRORS OF THE PAST IN WHICH STUDENTS WERE
TAUGHT ALREADY OUTDATED FACTUAL INFORMATION AND, SO
EQUIPPED, WENT FORTH TO INHIBIT FUTURE DEVELOPMENT
BEYOND THE NARROW CONFINES OF THE LITTLE THEY KNEW.
Conclusions
IT IS NOT POSSIBLE FOR ANY INDIVIDUAL TO KNOW EVEN 10% OF THE TOTAL AVAILABLE KNOWLEDGE
ABOUT CONCRETE
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